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Dispersal under Duress : The Ecology of Phenotypically Plastic Passive Dispersal by the Invasive Species Carduus Nutans

Author:
Teller, Brittany
Published:
[University Park, Pennsylvania] : Pennsylvania State University, 2014.
Physical Description:
1 electronic document
Additional Creators:
Shea, Katriona
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Restrictions on Access:
Open Access.
Summary:
Dispersal is a critical life history transition for many organisms. Successful dispersal is dependent on context, especially in heterogeneous landscapes, because individuals can only survive, grow, and reproduce in suitable habitat. Context may be especially important for passively dispersed species, including plants, because individuals cannot 'choose' the habitat in which they settle. The phenotypic plasticity of dispersal traits may be advantageous in these species. However, despite its potential importance, not much is known about the phenotypic plasticity of dispersal traits in plants, or the ecological implications of plastic trait responses. Here, I examine the phenotypic plasticity of dispersal traits using both empirical and theoretical approaches. I begin in Chapter 1 by presenting an introduction to phenotypic plasticity and dispersal. In Chapter 2, I show that dispersal phenotypic plasticity can maintain metapopulation growth rates in heterogeneous environments. This chapter also shows that highly dispersive species that are not phenotypically plastic may be especially vulnerable to population decline in the context of habitat degradation and destruction. In Chapters 3-5, I show that dispersal traits in the invasive thistle Carduus nutans (Asteraceae) plastically respond to drought, herbivore damage, and increases in temperature under experimental conditions. In each of these chapters, I use my empirical data in theoretical models of dispersal or spread to show how observed phenotypic plasticity in individuals can affect population-level outcomes. Finally, in Chapter 6, I shift my focus from plasticity to within-maternal capitulum variation, and show that differences among siblings can contribute to important differences in projections of spatial dynamics. My research shows that phenotypically plastic dispersal traits, and differences between individual seeds from the same mother, can be important factors affecting movement across landscapes. This research thus represents a significant step forward for our ecological understanding of how passively dispersed species move. Since passively dispersed species often form the base of food webs, and may be affected by changes in their environment, this research also contributes to a better understanding of how species might respond to new challenges brought about by climate change.
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Dissertation Note:
Ph.D. Pennsylvania State University 2014.
Reproduction Note:
Microfilm (positive). 1 reel 35 mm. (University Microfilms 103-08340)
Technical Details:
The full text of the dissertation is available as an Adobe Acrobat .pdf file ; Adobe Acrobat Reader required to view the file.
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